The present invention relates to a prosthetic tibial component, and particularly to a tibial tray component that compensates for bone removed from the posterior proximal tibia. More particularly, the present invention relates to a tibial tray component that has a cross-section that is configured for coupling to a proximal tibia resected to remove a greater amount of bone from the posterior end of the proximal tibia than from the anterior end of the proximal tibia.
Surgeons often replace damaged or diseased knees with conventional femoral and tibial components that cooperate to create a prosthetic articulating joint. See, for example, U.S. Pat. No. 4,759,767, entitled "Prosthesis for Tibial Component of Knee Joint," to James A. Lacey. These conventional tibial components often include a tibial tray that replaces the natural tibial plateau in the prosthetic joint. During traditional primary or revision surgery, good bone is often removed to accommodate the conventional prosthetic implant. It is desirable to minimize the removal of good tibial bone during surgery. In addition, surgeons replace diseased or damaged bone with augments or modular components shown in, for example U.S. Pat. No. 5,019,103, entitled "Tibial Wedge System," to Richard R. Van Zile et al., and U.S. Pat. No. 5,370,693, entitled "Orthopedic Implant Augmentation and Stabilization Device," to David C. Kelman et al., to "fill" the aperture left in the tibia following bone removal. What is needed is a tibial tray component that is suitable for use in both primary and revision surgery that minimizes the necessary amount of tibial bone removal.
According to the present invention, a tibial tray apparatus is provided. The tibial tray apparatus is suitable for replacing at least a portion of the proximal end of a tibia having an anterior end, a posterior end, and a resected surface extending between the anterior and posterior ends. The tibial tray apparatus includes a posterior compensation element that includes a proximal surface, an opposite distal surface configured for extension across the resected surface between the anterior and posterior sides, and a side wall extending between the proximal and distal surfaces. The side wall includes an anterior region having an anterior height and a posterior region having a posterior height. The posterior height of the posterior region is greater than the anterior height of the anterior region.
According to another embodiment of the present invention, a tibial tray apparatus suitable for replacing at least a portion of the proximal end of a tibia is provided. The tibial tray apparatus comprises a plateau element that includes a proximal surface, an opposite distal surface, and a side wall extending between the proximal and distal surfaces. The side wall has an anterior region with an anterior height and an opposite posterior region with a posterior height. The posterior height is greater than the anterior height. In addition, the tibial tray apparatus includes a stem that extends from the distal surface of the plateau element.
In yet another embodiment of the present invention, a prosthetic apparatus is provided that is suitable for replacing at least a portion of a tibia. The prosthetic apparatus comprises a tibial tray including a plateau having proximal and distal surfaces cooperating to define an anterior region with an anterior height and an opposite posterior region with a posterior height. The posterior height is greater than the anterior height. In addition, the prosthetic apparatus includes a stem that extends from the distal surface and is positioned to lie between the anterior region and the posterior region. Further, a stem extension is provided that includes an interior surface defining a stem-receiving cavity therein. The interior surface is configured for locking engagement with the stem of the tibial tray component.
In still another embodiment of the present invention, a method of replacing a proximal end of a tibia that includes a posterior end and an opposite anterior end is provided. The method comprises the steps of forming a resected surface of the proximal tibia to have a distal posterior slope and providing a generally wedge-shape plateau component having a proximal surface and an opposite distal surface. The distal surface diverges from the proximal surface by a downward posterior angle to form an anterior region with an anterior height and a posterior region with a posterior height that is greater than the anterior height. In addition, the method further includes the step of positioning the distal surface of the plateau on the resected surface so that posterior region of the plateau is adjacent the posterior end.
Additional features of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.